Seed coat The seed is covered by two coverings (layers). The outer layer is thick and tough called testa. The inner one is thin and whitish called tegmen. Hilum The concave side of seed is darker with a whitish elongated oval scar called hilum. Micropyle It is the small pore present at the end of hilum. It takes part in absorbing the water during seed germination. Cotyledons They are also called seed leaves. The two cotyledons are attached to embryo axis in between the plumule and radicle. Cotyledons are large, white, kidney-shaped. They store food